What year and what “MK” bikes do I have
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rvich
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The 72 is in the VIN range for Combat bikes but they produced both varieties. The only way to be sure is to look under the headsteady for a "C" stamped on the head and measure the cam lift.
There were no Combats made by the factory in 1971. (This is apparently completely wrong. I appoligize for the fake news.)
PS - what carbs are on these bikes?
There were no Combats made by the factory in 1971. (This is apparently completely wrong. I appoligize for the fake news.)
PS - what carbs are on these bikes?
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As no one else has jumped in, I think you'll find the 20M3 is a throwback to when the Commando was referred to as the Atlas Mk3 (20 being the Atlas Model No) The S denotes points driven from the camshaft...
rvich
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Somebody here will chime in who is more expert than I, however the earlier VIN numbers had the extra digits. I'm not exactly sure when it was dropped but basically 1972 production. I asked about the carbs because the intake ports offer some information about what you have for a head. The aftermarket carbs aren't a clue (for me anyway).
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That would be a MkIV.
That depends on the model. As stated, it's probably not a Combat.
If a Roadster then MkII (no MkIII Roadster).
If a Fastback then MkIII.
20M3S was the standard engine number prefix for a camshaft points engine prior to 200000 when the prefix was discontinued.
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There are 5 engine series in the commando run. 20M3, 20M3S, 200000, 300000, 325000+
These are engine series identifier. They do not strictly follow model or calendar year designations.
Amateurs with letter and number punches sometime wreck havoc on these bikes so be aware.
The VIN/SN do not include the engine identifier prefix
These are engine series identifier. They do not strictly follow model or calendar year designations.
Amateurs with letter and number punches sometime wreck havoc on these bikes so be aware.
The VIN/SN do not include the engine identifier prefix
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Yes, the 750 Roadster went from MkII to MkIV.
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A couple of visibles to tell if Combat.
The spacing between the head and Barrel is noticeably tighter on Combat, head shaved 40 thou or so.
compare the two.
Another inaccurate way is the Combat was the first 'Factory' black barrels, non Combat silver barrels.
I say inaccurate because most people have painted the barrels black, however, if they are silver, chances are it is not a Combat.
The spacing between the head and Barrel is noticeably tighter on Combat, head shaved 40 thou or so.
compare the two.
Another inaccurate way is the Combat was the first 'Factory' black barrels, non Combat silver barrels.
I say inaccurate because most people have painted the barrels black, however, if they are silver, chances are it is not a Combat.
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What month/year is on the red ID plate on the ‘72?
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Dave this very much verifies the concept that bikes did not always flow by SN very well.
My 201664 and 202206 are both DEC 71 with an early 06-1441 cert plate(Andover, England). This seems to be in conflict with the 72 parts book?
While 206344 shows APR 1972 with a 06-3247 cert plate.(GVWR 859 lbs)
I am not a fan of the MK designations due to these type of ambiguous inconsistencies. I wonder the competency of the originator or implementor of this MK system.
All three of the above bikes are full "combat tune". So rvich IMO is incorrect.
If it was up to me, this is generally how it would flow...
Roadster MKI = S1 rolling chassis 20M3S drive, electric harness 1
Roadster MKII = S2A-1 rolling chassis 20M3S drive, electric harness 2
Roadster MKIII = S2A rolling chassis 200000 drive, electric harness 3 L679 bullet tail light
Roadster MKIV = S2A rolling chassis 200000 drive, electric harness 3 917 square tail light/black clock holders
Not sure what clarity or distinction is made by the current system? engine tune...standard? combat tune? RH4? RH5?
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I diddnt think there was a Mk 111 roadster???
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Neither did the rocket scientist that made this current system...LOL
Maybe my system is better ? as I said "If it was up to me, this is generally how it would flow..."
I would probably just continue my numbering system with the 850's
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There isn't, or at least wasn't, as far as is known unless you happen to read Norvil's inaccurate and misleading Commando model identification list.
The factory must've realised they'd created a 'mark' monster by the 200000 series as that would have resulted in a...
MkII Hi-Rider
MkII Fastback LR
MkIII Roadster
MkIV Fastback
New Interstate (so no 'mark' at this time)
....yet all were built to basically the same 'production season' standard (I hesitate to use the term 'model year') which seems to be why the factory decided they should be MkIVs (with the possible exception of the new Interstate which was 'Interstate' for the first production season).
From 220000 750 models became MkV, thus...
Roadster MkV
Hi-Rider MkV
Interstate MkV
(Fastback and FB LR both discontinued).
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rvich
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OK. I stand corrected. The Norton factory apparently put out Combats whenever they felt like it. Sorry for contributing to the myth that they were produced for the 1972 model year.
This is how it goes with these bikes. You either delve into the very arcane minutiae or you are wrong!
This is how it goes with these bikes. You either delve into the very arcane minutiae or you are wrong!
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The engines had the 20M3 or 20M3S engine prefix.
The "original" VIN/SN plate did not have the engine prefix digits
It's only a small technicality that is incorrect, like male/female... basically the same thing right! LOL
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